An extensive motion picture film record of social play behavior of the California ground squirrel has been made. This film is being used to quantitatively describe the play behavior and to examine whether any metacommunication takes place in conjunction with play. In the laboratory, an experiment will be undertaken to deprive young squirrels of social play, while control animals will be allowed to play. The effects of this play deprivation on the social behavior of adults will be subsequently tested by paired encounters with nondeprived squirrels. The study will increase our understanding of play in animals, and may provide clues to the function of play in humans.